The present invention relates to computer keyboard support structures.
With increased computer usage in the home and office, a very common injury is repetitive stress injury, including Carpal Tunnel Syndrome (CTS). A major cause of CTS is repetitive motion, e.g., typing at a computer for an extended period of time. During the act of typing, the flexor tendons leading from the forearm to the thumb and fingers rub against the interior wall of the carpal tunnel. Without breaks in the movement or changing wrist position, tendons become inflamed due to an increase in intracarpal pressure (ICP) which, in turn, leads to a lack of proper blood flow. If the tendons in the carpal tunnel become inflamed, pressure may be put on the medial nerve at the wrist thereby causing pain, numbness, tingling, and weakness in the thumb and fingers.
CTS caused by typing can be prevented with proper posture, proper typing technique, proper equipment set up, and exercise. Not surprisingly, devices have been introduced to minimize the risk of developing CTS from typing. One such device is disclosed by U.S. Pat. No. 5,564,844 (the xe2x80x9c""844 patentxe2x80x9d), which discloses a cam-driven platform onto which a keyboard is placed. The platform is hinged to a base plate, and a motorized cam moves the platform from a horizontal position to an angled position above horizontal. The ""844 patent is designed to minimize the possibility of developing CTS by preventing the wrist from remaining in the same position for an extended period of time while typing.
In order to provide the most beneficial range of motion, it happens that a device such as the ""844 patent should move the wrist through what is known as the xe2x80x9cneutral zone.xe2x80x9d The neutral zone is a zone of wrist movement in which the wrist is moved from a point of flexion approximately thirty-five degrees (35xc2x0) below horizontal, across the horizontal (zero degrees), to a point of extension fifteen degrees (15xc2x0) above horizontal. On the other hand, wrist movement outside the neutral zone, i.e., beyond thirty degrees below horizontal or fifteen degrees above horizontal, excessive flexion without opposing extension, or excessive extension without opposing flexion, can cause unacceptable ICP greatly increasing the likelihood of developing CTS.
The design of the ""844 patent, unfortunately, does not appear to allow the platform to move in such a manner that causes the wrist to move through the neutral zone while typing. More specifically, the ""844 patent does not appear to provide any wrist flexion. As a result, the ""844 patent forces the user into excessive extension without any opposing flexion. As recognized herein, the ""844 patent consequently does not provide the full range of motion necessary to completely minimize the risk of developing CTS.
The present invention has recognized these prior art drawbacks, and has provided the below-disclosed solutions to one or more of the prior art deficiencies. More specifically, the present invention provides a keyboard support platform that moves continuously from an angle below horizontal, through a horizontal position, and to an angle above horizontal.
A keyboard support platform includes a base, a keyboard support plate hingedly attached to the base, and a drive assembly that further includes a motor coupled to the keyboard support plate. The drive assembly pivots the support plate with respect to the base from a position below horizontal, across a horizontal position, to a position above horizontal. Alternatively, the motorized drive assembly can be replaced by an inflatable air bladder, as described further below.
In a preferred embodiment, the keyboard support platform includes a limiting mechanism that is electrically coupled to the motor. Preferably, the limiting mechanism cycles the keyboard support plate back and forth across the horizontal position. In a presently preferred embodiment, the base includes a rear plate, a left side plate that extends from the rear plate, a right side plate that extends from the rear plate, a front plate that connects the left side plate and the right side plate, and a bottom plate that supports the rear plate, the left side plate, the right side plate, and the front plate. Preferably, the keyboard support plate is hingedly attached to the rear plate.
Also, in a preferred embodiment, the drive assembly includes a stationary block that is attached to the bottom plate, at least two guide rails that extend from the rear plate to the stationary block, a moving block that is slidably disposed on the guide rails, and a drive screw that is threadably engaged with the moving block and coupled to the motor. As intended by the present invention, as the drive screw rotates, it urges the moving block to move linearly. The keyboard support platform also includes a moving arm that is pivotably attached to the moving block and the keyboard support plate. Preferably, as the moving block moves, the moving arm urges the support plate to pivot with respect to the rear plate. In another embodiment of the present invention, a keyboard support platform includes a base that has a pivot plate extending from a bottom plate and a keyboard support plate that is hingedly attached to the pivot plate. This embodiment also includes a moving block that is slidably disposed relative to the pivot plate and a drive screw that is engaged with the moving block. The drive screw urges the moving block to move linearly as the drive screw rotates. Additionally, a moving arm is pivotably attached to the moving block and the keyboard support plate. As described in detail below, the moving arm urges the keyboard support plate to pivot with respect to the pivot plate.
In yet another embodiment of the present invention, a method for continuously cycling a computer keyboard from a tilt up orientation, through a horizontal orientation, to a tilt down orientation includes providing a keyboard support platform, placing a computer keyboard on the platform, and then moving the platform between the tilt up and tilt down orientations.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: